I never heard about this diet, but positive thinking is definitely helpful. I know a lot of people start dieting and lose motivation in the process, sometimes frustration can get overwhelming, especially if you're surrounded by friends who are fitter than you.
People who want to lose weight should stop obsessing over a number, and just start living a healthier lifestyle. I saw on Dr. Oz a scale called quantum scale that doesn't even tell you what your weight is, but it records it and lets you know when you're progressing. In my opinion, that's great and it helps with the whole positive attitude towards your own body. There is no ideal weight or height, it's all about feeling good about yourself